// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
//
//  DIYDrones Custom Mediatek GPS driver for ArduPilot and ArduPilotMega.
//	Code by Michael Smith, Jordi Munoz and Jose Julio, DIYDrones.com
//
//	This library is free software; you can redistribute it and / or
//	modify it under the terms of the GNU Lesser General Public
//	License as published by the Free Software Foundation; either
//	version 2.1 of the License, or (at your option) any later version.
//
//	GPS configuration : Custom protocol per "Customize Function Specification, 3D Robotics, v1.6"
//
#ifndef AP_GPS_MTK16_h
#define AP_GPS_MTK16_h

#include "GPS.h"
#include "AP_GPS_MTK_Common.h"

class AP_GPS_MTK16 : public GPS {
public:
	AP_GPS_MTK16(Stream *s);
	virtual void	init(void);
	virtual bool	read(void);

private:
// XXX this is being ignored by the compiler #pragma pack(1)
	struct diyd_mtk_msg {
		int32_t		latitude;
		int32_t		longitude;
		int32_t		altitude;
		int32_t		ground_speed;
		int32_t		ground_course;
		uint8_t		satellites;
		uint8_t		fix_type;
		uint32_t	utc_date;
		uint32_t	utc_time;
		uint16_t	hdop;
	};
// #pragma pack(pop)
	enum diyd_mtk_fix_type {
		FIX_NONE = 1,
		FIX_2D = 2,
		FIX_3D = 3
	};

	enum diyd_mtk_protocol_bytes {
		PREAMBLE1 = 0xd0,
		PREAMBLE2 = 0xdd,
	};

	// Packet checksum accumulators
	uint8_t 	_ck_a;
	uint8_t 	_ck_b;

	// State machine state
	uint8_t 	_step;
	uint8_t		_payload_counter;
	
	// Time from UNIX Epoch offset
	long		_time_offset;
	bool		_offset_calculated;

	// Receive buffer
	union {
		diyd_mtk_msg	msg;
		uint8_t			bytes[];
	} _buffer;
};

#endif	// AP_GPS_MTK16_H
